This bug crops up from time to time and cause fasmw to crash, It happens in the save dialog, when this crash happens the filename in the 'filename:' text box is trashed, then sooner rather than later fasmw will crash. The crash dump below should help in solving this mystery.
*----> State Dump for Thread Id 0xac4 <----*
eax=00000001 ebx=00a40000 ecx=0006f5ec edx=7c90eb94 esi=00a40000 edi=00000000
eip=0040e35d esp=0006f63c ebp=0006f8d4 iopl=0 nv up ei pl nz na po nc
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000206
*** ERROR: Module load completed but symbols could not be loaded for C:\FASMWIN - DirectX Library\FASMW.EXE
function: FASMW
0040e2fa ffff ???
0040e2fc 89c7 mov edi,eax
0040e2fe 31c0 xor eax,eax
0040e300 b904000000 mov ecx,0x4
0040e305 f3ab rep stosd
0040e307 b820202020 mov eax,0x20202020
0040e30c b93c000000 mov ecx,0x3c
0040e311 f3ab rep stosd
0040e313 31c0 xor eax,eax
0040e315 8985a8fdffff mov [ebp-0x258],eax
0040e31b 898588fdffff mov [ebp-0x278],eax
0040e321 898594fdffff mov [ebp-0x26c],eax
0040e327 40 inc eax
0040e328 898598fdffff mov [ebp-0x268],eax
0040e32e 8985a4fdffff mov [ebp-0x25c],eax
0040e334 898584fdffff mov [ebp-0x27c],eax
0040e33a e838000000 call FASMW+0xe377 (0040e377)
0040e33f 0f821c010000 jb FASMW+0xe461 (0040e461)
0040e345 89851cfeffff mov [ebp-0x1e4],eax
0040e34b 89c7 mov edi,eax
0040e34d 31c0 xor eax,eax
0040e34f b940000000 mov ecx,0x40
0040e354 f3ab rep stosd
0040e356 c3 ret
0040e357 8bb578fdffff mov esi,[ebp-0x288]
FAULT ->0040e35d 8b1e mov ebx,[esi] ds:0023:00a40000=????????
0040e35f 89f0 mov eax,esi
0040e361 e8f3f9ffff call FASMW+0xdd59 (0040dd59)
0040e366 89de mov esi,ebx
0040e368 09f6 or esi,esi
0040e36a 75f1 jnz FASMW+0xe35d (0040e35d)
0040e36c c78578fdffff00000000 mov dword ptr [ebp-0x288],0x0
0040e376 c3 ret
0040e377 8b8508feffff mov eax,[ebp-0x1f8]
0040e37d 3b850cfeffff cmp eax,[ebp-0x1f4]
0040e383 740c jz FASMW+0xe391 (0040e391)
0040e385 818508feffff00010000 add dword ptr [ebp-0x1f8],0x100
0040e38f f8 clc
0040e390 c3 ret
0040e391 53 push ebx
0040e392 56 push esi
0040e393 8b9d14feffff mov ebx,[ebp-0x1ec]
0040e399 8bb518feffff mov esi,[ebp-0x1e8]
0040e39f 83bd10feffff10 cmp dword ptr [ebp-0x1f0],0x10
0040e3a6 721b jb FASMW+0xe3c3 (0040e3c3)
0040e3a8 39de cmp esi,ebx
0040e3aa 0f8488000000 je FASMW+0xe438 (0040e438)
0040e3b0 833eff cmp dword ptr [esi],0xffffffff
0040e3b3 7465 jz FASMW+0xe41a (0040e41a)
0040e3b5 81c600010000 add esi,0x100
0040e3bb 3bb518feffff cmp esi,[ebp-0x1e8]